C#: Extraction of ref modifier for fields.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp/Entities/Field.cs

@@ -30,6 +30,7 @@ public override void Populate(TextWriter trapFile)
             PopulateAttributes();
             ContainingType!.PopulateGenerics();
             PopulateNullability(trapFile, Symbol.GetAnnotatedType());
+            PopulateRefKind(trapFile, Symbol.RefKind);
 
             var unboundFieldKey = Field.Create(Context, Symbol.OriginalDefinition);
             trapFile.fields(this, (Symbol.IsConst ? 2 : 1), Symbol.Name, ContainingType, Type.TypeRef, unboundFieldKey);

csharp/ql/lib/semmle/code/csharp/Variable.qll

@@ -399,6 +399,12 @@ class Field extends Variable, AssignableMember, Attributable, TopLevelExprParent
   /** Holds if this field is `volatile`. */
   predicate isVolatile() { this.hasModifier("volatile") }
 
+  /** Holds if this is a `ref` field. */
+  predicate isRef() { this.getAnnotatedType().isRef() }
+
+  /** Holds if this is a `ref readonly` field. */
+  predicate isReadonlyRef() { this.getAnnotatedType().isReadonlyRef() }
+
   /** Holds if this field is `readonly`. */
   predicate isReadOnly() { this.hasModifier("readonly") }